Matrix converters may be used in electric and/or hybrid vehicles to accommodate delivery of relatively high power over a relatively wide range of operating voltages, while at the same time achieving galvanic isolation, relatively high power factors, low harmonic distortion, relatively high power density and low cost. For example, bidirectional isolated matrix converters may be used to deliver energy from an alternating current (AC) energy source, such as the single-phase grid electricity common in most residential and commercial buildings, to charge a direct current (DC) energy storage element, such as a high voltage rechargeable battery, in a vehicle.
A bidirectional matrix converter includes a high voltage DC bus capacitor that is coupled across the AC input interface. Under certain conditions, it is desirable to discharge the voltage across the DC bus capacitor. For example, if the high voltage DC energy source (battery) is disconnected from the AC input interface or if the bidirectional matrix converter is removed from the vehicle, the DC bus capacitor should be discharged to a safe voltage level.